Question

sin2x+2sin2x+3cos2x=0

Answer 1

sin2x+2sin2x+3cos2x=0

3sin2x + 3cos2x = 0 | : cos2x

3tg2x + 3 = 0

3tg2x = -3

tg2x = -1

2x = arctg(-1) + pik

2x = -pi/4 + pik

x = -pi/8 + pik/2, где k принадлежит к целым.